Transformer for low temperatures



May 9, 1967 HANS-JOACH|M HARLOFF 3,319,206

TRANSFORMER FOR LOW TEMPERATURES Filed March 22, 1965 FIG.2

aY d i ATTYS.

United States Patent 9 Claims. Cl. 336-218) For the adaptation of signallines leading from outside into a system operating at temperatures aboutthe absolute zero point to supraconducting band lines affected withextremely low wave resistance, transformers are necessary. However, theusual transformer materials have, at low temperatures, such low initialpermeabilities that they are no longer utilizable as transformermaterials.

The basic problem of the invention is to provide a transformer,especially an impulse transformer, which is capable at very lowtemperatures of fulfilling all the demands to be made on a transformer.This is achieved through the feature that the core consists of at leastone thin magnetic layer with single-axial preferential direction of themagnetization, which layer is magnetized by a constant magnetic fieldinto the difficultly magnetizable direction, and in which themagnetization changes are utilized in the manner of the coherentrotation.

In the object of the invention there is utilized the concept that theanisotropic field strength of thin magnetic layers at low temperaturesis only about twice as great as at room temperature. With the aid of aconstant field acting in hard magnetization direction, which field hasto be greater than the anisotropic field strength, the magnetization isturned into the hard direction. The permeability of the layer in thedirection of easy magnetizability is then very high. Accordingly, theselayers can be used for high frequency transformers.

Two advantageous examples of the invention will be explained with theaid of the drawings, in which:

FIG. 1 is a perspective view, with a portion broken away, of acylindrical transformer construction; and

FIG. 2 is a perspective view of a transformer of fiat construction.

FIG. 1 illustrates a cylindrical form of transformer construction inwhich the magnetic layer is applied to a carrier body 1, preferablyconsisting of a supraconductive materail, which is traversed by a directcurrent. On it are coaxially disposed the primary winding 3 and thesecondary winding 4. The entire system is surrounded by an outercylindrical shell 2, the inner surface of which likewise carries a thinmagnetic layer and which, like the magnetic layer applied to the carrierbody 1, has an axial preferential direction. This outer magnetic layerserves as a return path for the magnetic flux components acting in axialdirection. Thereby the demagnetization factor of the layers in axialdirection remains small. In order to achieve as high as possible anefiiciency of these transformers an effort is made to raise theinductance. This is accomplished by using supraconductive material forthe limitation of the magnetic scatter field. The cylinder 2 has,therefore, on its outer surface a layer of supraconducting material, sothat all the magnetic fields remain substantially restricted to theinterior space. The polarity of the secondary impulses can be reversed,in a known manner, by reversal of the flow direction of the directcurrent in the carrier body, if the body 1 carrying the inner magneticlayer is utilized as a secondary line.

FIG. 2 illustrates a transformer of fiat construction, which can beproduced in especially simple form by utilizing vaporizing-ontechniques. The reference numeral 1 designates the upper magnetic layer,2 the secondary circuit, 3 the primary circuit, 4 the lower magneticlayer and 5 the carrier layer. The two supraconducting layers whichterminate the system at the top and bottom have the designation S. Inthis arrangement, too, the supraconducting layers serve for the spatiallimiting of the scatter field. A polarity reversal through the reversalof the constant field can be achieved when the secondary winding isarranged perpendicular to the primary circuit instead of parallel.

Changes may be made within the scope and spirit of the appended claimswhich define what is believed to be new and desired to have protected byLetters Patent.

I claim:

1. A transformer, especially an impulse transformer, for use attemperatures near the absolute zero point, comprising at least one coreand two windings, one of which forms a primary winding and the other asecondary winding, the core having at least one thin magnetic layer withmonoaxial preferential direction of magnetization, which is magnetizedby a contant magnetic field in the difficultly magnetizable directionwhereby the magnetization changes can be utilized in the manner of thecoherent rotation.

2. A transformer according to claim 1, wherein said core is in the formof a carrier body provided with a thin magnetizable layer on which bodyseveral wire windings are disposed, and a cylindrical shell, having athin magnetizable layer on its inner surface, surrounding said body andwindings.

3. A transformer according to claim 2, wherein the material of the thinmagnetic layer of a cylindrical shell possesses an axial preferentialdirection.

4. A transformer according to claim 2, wherein the carrier body and thesurrounding cylindrical shell consist of supraconducting material.

5. A transformer according to claim 3, wherein at least the surroundingcylindrical shell carries an outer supraconducting layer.

6. A transformer according to claim 1, wherein the two windings consistof a respective fiat conductor, and the core of the transformercomprises two flat thin magnetic layers, between which the two flatconductors are disposed.

7. A transformer according to claim 6, wherein supraconducting layersare disposed exteriorly of the two thin magnetic layers.

8. A transformer according to claim 6, wherein the secondary conductorextends perpendicular to the primary conductor.

9. A transformer according to claim 7, wherein the secondary conductorextends perpendicular to the primary conductor.

References Cited by the Examiner UNITED STATES PATENTS 3,102,973 9/1963Kunzler 317-158 3,210,707 10/1965 Constantakes 336-200 BERNARD A.GILHEANY, Primary Examiner.

G. HARRIS, JR., Assistant Examiner.

1. A TRANSFORMER, ESPECIALLY AN IMPULSE TRANSFORMER, FOR USE ATTEMPERATURES NEAR THE ABSOLUTE ZERO POINT, COMPRISING AT LEAST ONE COREAND TWO WINDINGS, ONE OF WHICH FORMS A PRIMARY WINDING AND THE OTHER ASECONDARY WINDING, THE CORE HAVING AT LEAST ONE THIN MAGNETIC LAYER WITHMONOAXIAL PREFERENTIAL DIRECTION OF MAGNETIZATION, WHICH IS MAGNETIZEDBY A CONTANT MAGNETIC FIELD IN THE DIFFICULTY MAGNETIZABLE DIRECTIONWHEREBY THE MAGNETIZATION CHANGES CAN BE UTILIZED IN THE MANNER OF THECOHERENT ROTATION.